SELECTIVE SYMBOL MEASUREMENT FOR POSITIONING
A method of measuring a wireless OFDM PRS at a user equipment includes: selecting a symbol subset of a symbol group of the OFDM PRS, the OFDM PRS comprising a slot of symbols comprising the symbol group, the symbol group consisting of a first symbol quantity of consecutive ones of the symbols, the symbol group being fully staggered in frequency domain, the symbol subset consisting of a second symbol quantity of the symbols of the symbol group, the second symbol quantity being smaller than the first symbol quantity, and the symbol subset being less than fully staggered in the frequency domain; and measuring the symbol subset without measuring all of the symbols of the symbol group.
This application claims the benefit of U.S. Provisional Application No. 63/076,441, filed Sep. 10, 2020, entitled “SELECTIVE SYMBOL MEASUREMENT FOR POSITIONING,” which is assigned to the assignee hereof, and the entire contents of which are hereby incorporated herein by reference.
BACKGROUNDWireless communication systems have developed through various generations, including a first-generation analog wireless phone service (1G), a second-generation (2G) digital wireless phone service (including interim 2.5G and 2.75G networks), a third-generation (3G) high speed data, Internet-capable wireless service, a fourth-generation (4G) service (e.g., Long Term Evolution (LTE) or WiMax), a fifth-generation (5G) service, etc. There are presently many different types of wireless communication systems in use, including Cellular and Personal Communications Service (PCS) systems. Examples of known cellular systems include the cellular Analog Advanced Mobile Phone System (AMPS), and digital cellular systems based on Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Time Division Multiple Access (TDMA), the Global System for Mobile access (GSM) variation of TDMA, etc.
A fifth generation (5G) mobile standard calls for higher data transfer speeds, greater numbers of connections, and better coverage, among other improvements. The 5G standard, according to the Next Generation Mobile Networks Alliance, is designed to provide data rates of several tens of megabits per second to each of tens of thousands of users, with 1 gigabit per second to tens of workers on an office floor. Several hundreds of thousands of simultaneous connections should be supported in order to support large sensor deployments. Consequently, the spectral efficiency of 5G mobile communications should be significantly enhanced compared to the current 4G standard. Furthermore, signaling efficiencies should be enhanced and latency should be substantially reduced compared to current standards.
SUMMARYAn example user equipment includes: a receiver configured to receive a wireless orthogonal frequency division multiplexed (OFDM) positioning reference signal (PRS); a memory; and a processor, communicatively coupled to the receiver and the memory, configured to: select a symbol subset of a symbol group of the OFDM PRS, the OFDM PRS comprising a slot of symbols comprising the symbol group, the symbol group consisting of a first symbol quantity of consecutive ones of the symbols, the symbol group being fully staggered in frequency domain, the symbol subset consisting of a second symbol quantity of the symbols of the symbol group, the second symbol quantity being smaller than the first symbol quantity, and the symbol subset being less than fully staggered in the frequency domain; and measure the symbol subset without measuring all of the symbols of the symbol group.
An example method of measuring a wireless OFDM PRS at a user equipment includes: selecting a symbol subset of a symbol group of the OFDM PRS, the OFDM PRS comprising a slot of symbols comprising the symbol group, the symbol group consisting of a first symbol quantity of consecutive ones of the symbols, the symbol group being fully staggered in frequency domain, the symbol subset consisting of a second symbol quantity of the symbols of the symbol group, the second symbol quantity being smaller than the first symbol quantity, and the symbol subset being less than fully staggered in the frequency domain; and measuring the symbol subset without measuring all of the symbols of the symbol group.
Another example user equipment includes: means for receiving a wireless OFDM PRS; means for selecting a symbol subset of a symbol group of the OFDM PRS, the OFDM PRS comprising a slot of symbols comprising the symbol group, the symbol group consisting of a first symbol quantity of consecutive ones of the symbols, the symbol group being fully staggered in frequency domain, the symbol subset consisting of a second symbol quantity of the symbols of the symbol group, the second symbol quantity being smaller than the first symbol quantity, and the symbol subset being less than fully staggered in the frequency domain; and means for measuring the symbol subset without measuring all of the symbols of the symbol group.
A non-transitory, processor-readable storage medium includes processor-readable instructions configured to cause a processor of a user equipment, in order to measure a wireless OFDM PRS, to: select a symbol subset of a symbol group of the OFDM PRS, the OFDM PRS comprising a slot of symbols comprising the symbol group, the symbol group consisting of a first symbol quantity of consecutive ones of the symbols, the symbol group being fully staggered in frequency domain, the symbol subset consisting of a second symbol quantity of the symbols of the symbol group, the second symbol quantity being smaller than the first symbol quantity, and the symbol subset being less than fully staggered in the frequency domain; and measure the symbol subset without measuring all of the symbols of the symbol group.
Techniques are discussed herein for selectively measuring resource elements of a positioning reference signal. For example, a user equipment (UE) may determine to measure fewer than all available resource elements of a positioning reference signal, e.g., to conserve processing operations/processing resources and/or processing power. The UE may determine to measure fewer than all the available resource elements before or after measuring resource elements of the reference signal. For example, the UE may measure a fully-staggered group of resource elements of a reference signal and determine a timing of a peak of the reference signal. The UE may determine to reduce a processing amount and or a power consumption for processing further resource elements of the reference signal based on one or more factors. For example, the UE may determine a confidence for identifying a correct peak from among aliased peaks of the reference signal due to measuring one or more options of less-than-fully-staggered collections of the resource elements. The UE may consider a battery level of the UE, scheduled resource elements, a desired power reduction, a desired processing operations reduction, a period between reference signal occasions to be measured, a number of peaks in options for less-than-fully staggered measurements, movement of the UE, Doppler measurement, whether the UE is moving closer to a base station, whether the UE is moving further away from a base station, etc. The UE may use a combination of multiple factors to determine whether to reduce measurement, by how much, and what measurement option to use. The UE may use machine-learning, e.g., a neural network, to make such determinations. Other examples, however, may be implemented.
Items and/or techniques described herein may provide one or more of the following capabilities, as well as other capabilities not mentioned. User equipment power usage may be reduced for positioning, e.g., for tracking. Processing operations for positioning at a user equipment may be reduced. Network efficiency for positioning may be improved. Measurement gaps for measuring positioning reference signals may be reduced. Other capabilities may be provided and not every implementation according to the disclosure must provide any, let alone all, of the capabilities discussed.
Obtaining the locations of mobile devices that are accessing a wireless network may be useful for many applications including, for example, emergency calls, personal navigation, consumer asset tracking, locating a friend or family member, etc. Existing positioning methods include methods based on measuring radio signals transmitted from a variety of devices or entities including satellite vehicles (SVs) and terrestrial radio sources in a wireless network such as base stations and access points. It is expected that standardization for the 5G wireless networks will include support for various positioning methods, which may utilize reference signals transmitted by base stations in a manner similar to which LTE wireless networks currently utilize Positioning Reference Signals (PRS) and/or Cell-specific Reference Signals (CRS) for position determination.
The description may refer to sequences of actions to be performed, for example, by elements of a computing device. Various actions described herein can be performed by specific circuits (e.g., an application specific integrated circuit (ASIC)), by program instructions being executed by one or more processors, or by a combination of both. Sequences of actions described herein may be embodied within a non-transitory computer-readable medium having stored thereon a corresponding set of computer instructions that upon execution would cause an associated processor to perform the functionality described herein. Thus, the various aspects described herein may be embodied in a number of different forms, all of which are within the scope of the disclosure, including claimed subject matter.
As used herein, the terms “user equipment” (UE) and “base station” are not specific to or otherwise limited to any particular Radio Access Technology (RAT), unless otherwise noted. In general, such UEs may be any wireless communication device (e.g., a mobile phone, router, tablet computer, laptop computer, consumer asset tracking device, Internet of Things (IoT) device, etc.) used by a user to communicate over a wireless communications network. A UE may be mobile or may (e.g., at certain times) be stationary, and may communicate with a Radio Access Network (RAN). As used herein, the term “UE” may be referred to interchangeably as an “access terminal” or “AT,” a “client device,” a “wireless device,” a “subscriber device,” a “subscriber terminal,” a “subscriber station,” a “user terminal” or UT, a “mobile terminal,” a “mobile station,” a “mobile device,” or variations thereof. Generally, UEs can communicate with a core network via a RAN, and through the core network the UEs can be connected with external networks such as the Internet and with other UEs. Of course, other mechanisms of connecting to the core network and/or the Internet are also possible for the UEs, such as over wired access networks, WiFi networks (e.g., based on IEEE 802.11, etc.) and so on.
A base station may operate according to one of several RATs in communication with UEs depending on the network in which it is deployed. Examples of a base station include an Access Point (AP), a Network Node, a NodeB, an evolved NodeB (eNB), or a general Node B (gNodeB, gNB). In addition, in some systems a base station may provide purely edge node signaling functions while in other systems it may provide additional control and/or network management functions.
UEs may be embodied by any of a number of types of devices including but not limited to printed circuit (PC) cards, compact flash devices, external or internal modems, wireless or wireline phones, smartphones, tablets, consumer asset tracking devices, asset tags, and so on. A communication link through which UEs can send signals to a RAN is called an uplink channel (e.g., a reverse traffic channel, a reverse control channel, an access channel, etc.). A communication link through which the RAN can send signals to UEs is called a downlink or forward link channel (e.g., a paging channel, a control channel, a broadcast channel, a forward traffic channel, etc.). As used herein the term traffic channel (TCH) can refer to either an uplink/reverse or downlink/forward traffic channel.
As used herein, the term “cell” or “sector” may correspond to one of a plurality of cells of a base station, or to the base station itself, depending on the context. The term “cell” may refer to a logical communication entity used for communication with a base station (for example, over a carrier), and may be associated with an identifier for distinguishing neighboring cells (for example, a physical cell identifier (PCID), a virtual cell identifier (VCID)) operating via the same or a different carrier. In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (for example, machine-type communication (MTC), narrowband Internet-of-Things (NB-IoT), enhanced mobile broadband (eMBB), or others) that may provide access for different types of devices. In some examples, the term “cell” may refer to a portion of a geographic coverage area (for example, a sector) over which the logical entity operates.
Referring to
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The system 100 is capable of wireless communication in that components of the system 100 can communicate with one another (at least some times using wireless connections) directly or indirectly, e.g., via the gNBs 110a, 110b, the ng-eNB 114, and/or the 5GC 140 (and/or one or more other devices not shown, such as one or more other base transceiver stations). For indirect communications, the communications may be altered during transmission from one entity to another, e.g., to alter header information of data packets, to change format, etc. The UE 105 may include multiple UEs and may be a mobile wireless communication device, but may communicate wirelessly and via wired connections. The UE 105 may be any of a variety of devices, e.g., a smartphone, a tablet computer, a vehicle-based device, etc., but these are examples as the UE 105 is not required to be any of these configurations, and other configurations of UEs may be used. Other UEs may include wearable devices (e.g., smart watches, smart jewelry, smart glasses or headsets, etc.). Still other UEs may be used, whether currently existing or developed in the future. Further, other wireless devices (whether mobile or not) may be implemented within the system 100 and may communicate with each other and/or with the UE 105, the gNBs 110a, 110b, the ng-eNB 114, the 5GC 140, and/or the external client 130. For example, such other devices may include internet of thing (IoT) devices, medical devices, home entertainment and/or automation devices, etc. The 5GC 140 may communicate with the external client 130 (e.g., a computer system), e.g., to allow the external client 130 to request and/or receive location information regarding the UE 105 (e.g., via the GMLC 125).
The UE 105 or other devices may be configured to communicate in various networks and/or for various purposes and/or using various technologies (e.g., 5G, Wi-Fi communication, multiple frequencies of Wi-Fi communication, satellite positioning, one or more types of communications (e.g., GSM (Global System for Mobiles), CDMA (Code Division Multiple Access), LTE (Long-Term Evolution), V2X (Vehicle-to-Everything, e.g., V2P (Vehicle-to-Pedestrian), V2I (Vehicle-to-Infrastructure), V2V (Vehicle-to-Vehicle), etc.), IEEE 802.11p, etc.). V2X communications may be cellular (Cellular-V2X (C-V2X)) and/or WiFi (e.g., DSRC (Dedicated Short-Range Connection)). The system 100 may support operation on multiple carriers (waveform signals of different frequencies). Multi-carrier transmitters can transmit modulated signals simultaneously on the multiple carriers. Each modulated signal may be a Code Division Multiple Access (CDMA) signal, a Time Division Multiple Access (TDMA) signal, an Orthogonal Frequency Division Multiple Access (OFDMA) signal, a Single-Carrier Frequency Division Multiple Access (SC-FDMA) signal, etc. Each modulated signal may be sent on a different carrier and may carry pilot, overhead information, data, etc. The UEs 105, 106 may communicate with each other through UE-to-UE sidelink (SL) communications by transmitting over one or more sidelink channels such as a physical sidelink synchronization channel (PSSCH), a physical sidelink broadcast channel (PSBCH), or a physical sidelink control channel (PSCCH).
The UE 105 may comprise and/or may be referred to as a device, a mobile device, a wireless device, a mobile terminal, a terminal, a mobile station (MS), a Secure User Plane Location (SUPL) Enabled Terminal (SET), or by some other name. Moreover, the UE 105 may correspond to a cellphone, smartphone, laptop, tablet, PDA, consumer asset tracking device, navigation device, Internet of Things (IoT) device, health monitors, security systems, smart city sensors, smart meters, wearable trackers, or some other portable or moveable device. Typically, though not necessarily, the UE 105 may support wireless communication using one or more Radio Access Technologies (RATs) such as Global System for Mobile communication (GSM), Code Division Multiple Access (CDMA), Wideband CDMA (WCDMA), LTE, High Rate Packet Data (HRPD), IEEE 802.11 WiFi (also referred to as Wi-Fi), Bluetooth® (BT), Worldwide Interoperability for Microwave Access (WiMAX), 5G new radio (NR) (e.g., using the NG-RAN 135 and the 5GC 140), etc. The UE 105 may support wireless communication using a Wireless Local Area Network (WLAN) which may connect to other networks (e.g., the Internet) using a Digital Subscriber Line (DSL) or packet cable, for example. The use of one or more of these RATs may allow the UE 105 to communicate with the external client 130 (e.g., via elements of the 5GC 140 not shown in
The UE 105 may include a single entity or may include multiple entities such as in a personal area network where a user may employ audio, video and/or data I/O (input/output) devices and/or body sensors and a separate wireline or wireless modem. An estimate of a location of the UE 105 may be referred to as a location, location estimate, location fix, fix, position, position estimate, or position fix, and may be geographic, thus providing location coordinates for the UE 105 (e.g., latitude and longitude) which may or may not include an altitude component (e.g., height above sea level, height above or depth below ground level, floor level, or basement level). Alternatively, a location of the UE 105 may be expressed as a civic location (e.g., as a postal address or the designation of some point or small area in a building such as a particular room or floor). A location of the UE 105 may be expressed as an area or volume (defined either geographically or in civic form) within which the UE 105 is expected to be located with some probability or confidence level (e.g., 67%, 95%, etc.). A location of the UE 105 may be expressed as a relative location comprising, for example, a distance and direction from a known location. The relative location may be expressed as relative coordinates (e.g., X, Y (and Z) coordinates) defined relative to some origin at a known location which may be defined, e.g., geographically, in civic terms, or by reference to a point, area, or volume, e.g., indicated on a map, floor plan, or building plan. In the description contained herein, the use of the term location may comprise any of these variants unless indicated otherwise. When computing the location of a UE, it is common to solve for local x, y, and possibly z coordinates and then, if desired, convert the local coordinates into absolute coordinates (e.g., for latitude, longitude, and altitude above or below mean sea level).
The UE 105 may be configured to communicate with other entities using one or more of a variety of technologies. The UE 105 may be configured to connect indirectly to one or more communication networks via one or more device-to-device (D2D) peer-to-peer (P2P) links. The D2D P2P links may be supported with any appropriate D2D radio access technology (RAT), such as LTE Direct (LTE-D), WiFi Direct (WiFi-D), Bluetooth®, and so on. One or more of a group of UEs utilizing D2D communications may be within a geographic coverage area of a Transmission/Reception Point (TRP) such as one or more of the gNBs 110a, 110b, and/or the ng-eNB 114. Other UEs in such a group may be outside such geographic coverage areas, or may be otherwise unable to receive transmissions from a base station. Groups of UEs communicating via D2D communications may utilize a one-to-many (1:M) system in which each UE may transmit to other UEs in the group. A TRP may facilitate scheduling of resources for D2D communications. In other cases, D2D communications may be carried out between UEs without the involvement of a TRP. One or more of a group of UEs utilizing D2D communications may be within a geographic coverage area of a TRP. Other UEs in such a group may be outside such geographic coverage areas, or be otherwise unable to receive transmissions from a base station. Groups of UEs communicating via D2D communications may utilize a one-to-many (1:M) system in which each UE may transmit to other UEs in the group. A TRP may facilitate scheduling of resources for D2D communications. In other cases, D2D communications may be carried out between UEs without the involvement of a TRP.
Base stations (BSs) in the NG-RAN 135 shown in
Base stations (BSs) in the NG-RAN 135 shown in
The gNBs 110a, 110b and/or the ng-eNB 114 may each comprise one or more TRPs. For example, each sector within a cell of a BS may comprise a TRP, although multiple TRPs may share one or more components (e.g., share a processor but have separate antennas). The system 100 may include macro TRPs exclusively or the system 100 may have TRPs of different types, e.g., macro, pico, and/or femto TRPs, etc. A macro TRP may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by terminals with service subscription. A pico TRP may cover a relatively small geographic area (e.g., a pico cell) and may allow unrestricted access by terminals with service subscription. A femto or home TRP may cover a relatively small geographic area (e.g., a femto cell) and may allow restricted access by terminals having association with the femto cell (e.g., terminals for users in a home).
Each of the gNBs 110a, 110b and/or the ng-eNB 114 may include a radio unit (RU), a distributed unit (DU), and a central unit (CU). For example, the gNB 110a includes an RU 111, a DU 112, and a CU 113. The RU 111, DU 112, and CU 113 divide functionality of the gNB 110a. While the gNB 110a is shown with a single RU, a single DU, and a single CU, a gNB may include one or more RUs, one or more DUs, and/or one or more CUs. An interface between the CU 113 and the DU 112 is referred to as an F1 interface. The RU 111 is configured to perform digital front end (DFE) functions (e.g., analog-to-digital conversion, filtering, power amplification, transmission/reception) and digital beamforming, and includes a portion of the physical (PHY) layer. The RU 111 may perform the DFE using massive multiple input/multiple output (MIMO) and may be integrated with one or more antennas of the gNB 110a. The DU 112 hosts the Radio Link Control (RLC), Medium Access Control (MAC), and physical layers of the gNB 110a. One DU can support one or more cells, and each cell is supported by a single DU. The operation of the DU 112 is controlled by the CU 113. The CU 113 is configured to perform functions for transferring user data, mobility control, radio access network sharing, positioning, session management, etc. although some functions are allocated exclusively to the DU 112. The CU 113 hosts the Radio Resource Control (RRC), Service Data Adaptation Protocol (SDAP), and Packet Data Convergence Protocol (PDCP) protocols of the gNB 110a. The UE 105 may communicate with the CU 113 via RRC, SDAP, and PDCP layers, with the DU 112 via the RLC, MAC, and PHY layers, and with the RU 111 via the PHY layer.
As noted, while
The gNBs 110a, 110b and the ng-eNB 114 may communicate with the AMF 115, which, for positioning functionality, communicates with the LMF 120. The AMF 115 may support mobility of the UE 105, including cell change and handover and may participate in supporting a signaling connection to the UE 105 and possibly data and voice bearers for the UE 105. The LMF 120 may communicate directly with the UE 105, e.g., through wireless communications, or directly with the gNBs 110a, 110b and/or the ng-eNB 114. The LMF 120 may support positioning of the UE 105 when the UE 105 accesses the NG-RAN 135 and may support position procedures/methods such as Assisted GNSS (A-GNSS), Observed Time Difference of Arrival (OTDOA) (e.g., Downlink (DL) OTDOA or Uplink (UL) OTDOA), Round Trip Time (RTT), Multi-Cell RTT, Real Time Kinematic (RTK), Precise Point Positioning (PPP), Differential GNSS (DGNSS), Enhanced Cell ID (E-CID), angle of arrival (AoA), angle of departure (AoD), and/or other position methods. The LMF 120 may process location services requests for the UE 105, e.g., received from the AMF 115 or from the GMLC 125. The LMF 120 may be connected to the AMF 115 and/or to the GMLC 125. The LMF 120 may be referred to by other names such as a Location Manager (LM), Location Function (LF), commercial LMF (CLMF), or value added LMF (VLMF). A node/system that implements the LMF 120 may additionally or alternatively implement other types of location-support modules, such as an Enhanced Serving Mobile Location Center (E-SMLC) or a Secure User Plane Location (SUPL) Location Platform (SLP). At least part of the positioning functionality (including derivation of the location of the UE 105) may be performed at the UE 105 (e.g., using signal measurements obtained by the UE 105 for signals transmitted by wireless nodes such as the gNBs 110a, 110b and/or the ng-eNB 114, and/or assistance data provided to the UE 105, e.g. by the LMF 120). The AMF 115 may serve as a control node that processes signaling between the UE 105 and the 5GC 140, and may provide QoS (Quality of Service) flow and session management. The AMF 115 may support mobility of the UE 105 including cell change and handover and may participate in supporting signaling connection to the UE 105.
The server 150, e.g., a cloud server, is configured to obtain and provide location estimates of the UE 105 to the external client 130. The server 150 may, for example, be configured to run a microservice/service that obtains the location estimate of the UE 105. The server 150 may, for example, pull the location estimate from (e.g., by sending a location request to) the UE 105, one or more of the gNBs 110a, 110b (e.g., via the RU 111, the DU 112, and the CU 113) and/or the ng-eNB 114, and/or the LMF 120. As another example, the UE 105, one or more of the gNBs 110a, 110b (e.g., via the RU 111, the DU 112, and the CU 113), and/or the LMF 120 may push the location estimate of the UE 105 to the server 150.
The GMLC 125 may support a location request for the UE 105 received from the external client 130 via the server 150 and may forward such a location request to the AMF 115 for forwarding by the AMF 115 to the LMF 120 or may forward the location request directly to the LMF 120. A location response from the LMF 120 (e.g., containing a location estimate for the UE 105) may be returned to the GMLC 125 either directly or via the AMF 115 and the GMLC 125 may then return the location response (e.g., containing the location estimate) to the external client 130 via the server 150. The GMLC 125 is shown connected to both the AMF 115 and LMF 120, though may not be connected to the AMF 115 or the LMF 120 in some implementations.
As further illustrated in
With a UE-assisted position method, the UE 105 may obtain location measurements and send the measurements to a location server (e.g., the LMF 120) for computation of a location estimate for the UE 105. For example, the location measurements may include one or more of a Received Signal Strength Indication (RSSI), Round Trip signal propagation Time (RTT), Reference Signal Time Difference (RSTD), Reference Signal Received Power (RSRP) and/or Reference Signal Received Quality (RSRQ) for the gNBs 110a, 110b, the ng-eNB 114, and/or a WLAN AP. The location measurements may also or instead include measurements of GNSS pseudorange, code phase, and/or carrier phase for the SVs 190-193.
With a UE-based position method, the UE 105 may obtain location measurements (e.g., which may be the same as or similar to location measurements for a UE-assisted position method) and may compute a location of the UE 105 (e.g., with the help of assistance data received from a location server such as the LMF 120 or broadcast by the gNBs 110a, 110b, the ng-eNB 114, or other base stations or APs).
With a network-based position method, one or more base stations (e.g., the gNBs 110a, 110b, and/or the ng-eNB 114) or APs may obtain location measurements (e.g., measurements of RSSI, RTT, RSRP, RSRQ or Time of Arrival (ToA) for signals transmitted by the UE 105) and/or may receive measurements obtained by the UE 105. The one or more base stations or APs may send the measurements to a location server (e.g., the LMF 120) for computation of a location estimate for the UE 105.
Information provided by the gNBs 110a, 110b, and/or the ng-eNB 114 to the LMF 120 using NRPPa may include timing and configuration information for directional SS transmissions and location coordinates. The LMF 120 may provide some or all of this information to the UE 105 as assistance data in an LPP and/or NPP message via the NG-RAN 135 and the 5GC 140.
An LPP or NPP message sent from the LMF 120 to the UE 105 may instruct the UE 105 to do any of a variety of things depending on desired functionality. For example, the LPP or NPP message could contain an instruction for the UE 105 to obtain measurements for GNSS (or A-GNSS), WLAN, E-CID, and/or OTDOA (or some other position method). In the case of E-CID, the LPP or NPP message may instruct the UE 105 to obtain one or more measurement quantities (e.g., beam ID, beam width, mean angle, RSRP, RSRQ measurements) of directional signals transmitted within particular cells supported by one or more of the gNBs 110a, 110b, and/or the ng-eNB 114 (or supported by some other type of base station such as an eNB or WiFi AP). The UE 105 may send the measurement quantities back to the LMF 120 in an LPP or NPP message (e.g., inside a 5G NAS message) via the serving gNB 110a (or the serving ng-eNB 114) and the AMF 115.
As noted, while the communication system 100 is described in relation to 5G technology, the communication system 100 may be implemented to support other communication technologies, such as GSM, WCDMA, LTE, etc., that are used for supporting and interacting with mobile devices such as the UE 105 (e.g., to implement voice, data, positioning, and other functionalities). In some such embodiments, the 5GC 140 may be configured to control different air interfaces. For example, the 5GC 140 may be connected to a WLAN using a Non-3GPP InterWorking Function (N3IWF, not shown
As noted, in some embodiments, positioning functionality may be implemented, at least in part, using the directional SS beams, sent by base stations (such as the gNBs 110a, 110b, and/or the ng-eNB 114) that are within range of the UE whose position is to be determined (e.g., the UE 105 of
Referring also to
The configuration of the UE 200 shown in
The UE 200 may comprise the modem processor 232 that may be capable of performing baseband processing of signals received and down-converted by the transceiver 215 and/or the SPS receiver 217. The modem processor 232 may perform baseband processing of signals to be upconverted for transmission by the transceiver 215. Also or alternatively, baseband processing may be performed by the processor 230 and/or the DSP 231. Other configurations, however, may be used to perform baseband processing.
The UE 200 may include the sensor(s) 213 that may include, for example, one or more of various types of sensors such as one or more inertial sensors, one or more magnetometers, one or more environment sensors, one or more optical sensors, one or more weight sensors, and/or one or more radio frequency (RF) sensors, etc. An inertial measurement unit (IMU) may comprise, for example, one or more accelerometers (e.g., collectively responding to acceleration of the UE 200 in three dimensions) and/or one or more gyroscopes (e.g., three-dimensional gyroscope(s)). The sensor(s) 213 may include one or more magnetometers (e.g., three-dimensional magnetometer(s)) to determine orientation (e.g., relative to magnetic north and/or true north) that may be used for any of a variety of purposes, e.g., to support one or more compass applications. The environment sensor(s) may comprise, for example, one or more temperature sensors, one or more barometric pressure sensors, one or more ambient light sensors, one or more camera imagers, and/or one or more microphones, etc. The sensor(s) 213 may generate analog and/or digital signals indications of which may be stored in the memory 211 and processed by the DSP 231 and/or the processor 230 in support of one or more applications such as, for example, applications directed to positioning and/or navigation operations.
The sensor(s) 213 may be used in relative location measurements, relative location determination, motion determination, etc. Information detected by the sensor(s) 213 may be used for motion detection, relative displacement, dead reckoning, sensor-based location determination, and/or sensor-assisted location determination. The sensor(s) 213 may be useful to determine whether the UE 200 is fixed (stationary) or mobile and/or whether to report certain useful information to the LMF 120 regarding the mobility of the UE 200. For example, based on the information obtained/measured by the sensor(s) 213, the UE 200 may notify/report to the LMF 120 that the UE 200 has detected movements or that the UE 200 has moved, and report the relative displacement/distance (e.g., via dead reckoning, or sensor-based location determination, or sensor-assisted location determination enabled by the sensor(s) 213). In another example, for relative positioning information, the sensors/IMU can be used to determine the angle and/or orientation of the other device with respect to the UE 200, etc.
The IMU may be configured to provide measurements about a direction of motion and/or a speed of motion of the UE 200, which may be used in relative location determination. For example, one or more accelerometers and/or one or more gyroscopes of the IMU may detect, respectively, a linear acceleration and a speed of rotation of the UE 200. The linear acceleration and speed of rotation measurements of the UE 200 may be integrated over time to determine an instantaneous direction of motion as well as a displacement of the UE 200. The instantaneous direction of motion and the displacement may be integrated to track a location of the UE 200. For example, a reference location of the UE 200 may be determined, e.g., using the SPS receiver 217 (and/or by some other means) for a moment in time and measurements from the accelerometer(s) and gyroscope(s) taken after this moment in time may be used in dead reckoning to determine present location of the UE 200 based on movement (direction and distance) of the UE 200 relative to the reference location.
The magnetometer(s) may determine magnetic field strengths in different directions which may be used to determine orientation of the UE 200. For example, the orientation may be used to provide a digital compass for the UE 200. The magnetometer(s) may include a two-dimensional magnetometer configured to detect and provide indications of magnetic field strength in two orthogonal dimensions. The magnetometer(s) may include a three-dimensional magnetometer configured to detect and provide indications of magnetic field strength in three orthogonal dimensions. The magnetometer(s) may provide means for sensing a magnetic field and providing indications of the magnetic field, e.g., to the processor 210.
The transceiver 215 may include a wireless transceiver 240 and a wired transceiver 250 configured to communicate with other devices through wireless connections and wired connections, respectively. For example, the wireless transceiver 240 may include a wireless transmitter 242 and a wireless receiver 244 coupled to an antenna 246 for transmitting (e.g., on one or more uplink channels and/or one or more sidelink channels) and/or receiving (e.g., on one or more downlink channels and/or one or more sidelink channels) wireless signals 248 and transducing signals from the wireless signals 248 to wired (e.g., electrical and/or optical) signals and from wired (e.g., electrical and/or optical) signals to the wireless signals 248. Thus, the wireless transmitter 242 may include multiple transmitters that may be discrete components or combined/integrated components, and/or the wireless receiver 244 may include multiple receivers that may be discrete components or combined/integrated components. The wireless transceiver 240 may be configured to communicate signals (e.g., with TRPs and/or one or more other devices) according to a variety of radio access technologies (RATs) such as 5G New Radio (NR), GSM (Global System for Mobiles), UMTS (Universal Mobile Telecommunications System), AMPS (Advanced Mobile Phone System), CDMA (Code Division Multiple Access), WCDMA (Wideband CDMA), LTE (Long-Term Evolution), LTE Direct (LTE-D), 3GPP LTE-V2X (PC5), IEEE 802.11 (including IEEE 802.11p), WiFi, WiFi Direct (WiFi-D), Bluetooth®, Zigbee etc. New Radio may use mm-wave frequencies and/or sub-6 GHz frequencies. The wired transceiver 250 may include a wired transmitter 252 and a wired receiver 254 configured for wired communication, e.g., a network interface that may be utilized to communicate with the NG-RAN 135 to send communications to, and receive communications from, the NG-RAN 135. The wired transmitter 252 may include multiple transmitters that may be discrete components or combined/integrated components, and/or the wired receiver 254 may include multiple receivers that may be discrete components or combined/integrated components. The wired transceiver 250 may be configured, e.g., for optical communication and/or electrical communication. The transceiver 215 may be communicatively coupled to the transceiver interface 214, e.g., by optical and/or electrical connection. The transceiver interface 214 may be at least partially integrated with the transceiver 215. The wireless transmitter 242, the wireless receiver 244, and/or the antenna 246 may include multiple transmitters, multiple receivers, and/or multiple antennas, respectively, for sending and/or receiving, respectively, appropriate signals.
The user interface 216 may comprise one or more of several devices such as, for example, a speaker, microphone, display device, vibration device, keyboard, touch screen, etc. The user interface 216 may include more than one of any of these devices. The user interface 216 may be configured to enable a user to interact with one or more applications hosted by the UE 200. For example, the user interface 216 may store indications of analog and/or digital signals in the memory 211 to be processed by DSP 231 and/or the general-purpose processor 230 in response to action from a user. Similarly, applications hosted on the UE 200 may store indications of analog and/or digital signals in the memory 211 to present an output signal to a user. The user interface 216 may include an audio input/output (I/O) device comprising, for example, a speaker, a microphone, digital-to-analog circuitry, analog-to-digital circuitry, an amplifier and/or gain control circuitry (including more than one of any of these devices). Other configurations of an audio I/O device may be used. Also or alternatively, the user interface 216 may comprise one or more touch sensors responsive to touching and/or pressure, e.g., on a keyboard and/or touch screen of the user interface 216.
The SPS receiver 217 (e.g., a Global Positioning System (GPS) receiver) may be capable of receiving and acquiring SPS signals 260 via an SPS antenna 262. The SPS antenna 262 is configured to transduce the SPS signals 260 from wireless signals to wired signals, e.g., electrical or optical signals, and may be integrated with the antenna 246. The SPS receiver 217 may be configured to process, in whole or in part, the acquired SPS signals 260 for estimating a location of the UE 200. For example, the SPS receiver 217 may be configured to determine location of the UE 200 by trilateration using the SPS signals 260. The general-purpose processor 230, the memory 211, the DSP 231 and/or one or more specialized processors (not shown) may be utilized to process acquired SPS signals, in whole or in part, and/or to calculate an estimated location of the UE 200, in conjunction with the SPS receiver 217. The memory 211 may store indications (e.g., measurements) of the SPS signals 260 and/or other signals (e.g., signals acquired from the wireless transceiver 240) for use in performing positioning operations. The general-purpose processor 230, the DSP 231, and/or one or more specialized processors, and/or the memory 211 may provide or support a location engine for use in processing measurements to estimate a location of the UE 200.
The UE 200 may include the camera 218 for capturing still or moving imagery. The camera 218 may comprise, for example, an imaging sensor (e.g., a charge coupled device or a CMOS imager), a lens, analog-to-digital circuitry, frame buffers, etc. Additional processing, conditioning, encoding, and/or compression of signals representing captured images may be performed by the general-purpose processor 230 and/or the DSP 231. Also or alternatively, the video processor 233 may perform conditioning, encoding, compression, and/or manipulation of signals representing captured images. The video processor 233 may decode/decompress stored image data for presentation on a display device (not shown), e.g., of the user interface 216.
The position device (PD) 219 may be configured to determine a position of the UE 200, motion of the UE 200, and/or relative position of the UE 200, and/or time. For example, the PD 219 may communicate with, and/or include some or all of, the SPS receiver 217. The PD 219 may work in conjunction with the processor 210 and the memory 211 as appropriate to perform at least a portion of one or more positioning methods, although the description herein may refer to the PD 219 being configured to perform, or performing, in accordance with the positioning method(s). The PD 219 may also or alternatively be configured to determine location of the UE 200 using terrestrial-based signals (e.g., at least some of the signals 248) for trilateration, for assistance with obtaining and using the SPS signals 260, or both. The PD 219 may be configured to use one or more other techniques (e.g., relying on the UE's self-reported location (e.g., part of the UE's position beacon)) for determining the location of the UE 200, and may use a combination of techniques (e.g., SPS and terrestrial positioning signals) to determine the location of the UE 200. The PD 219 may include one or more of the sensors 213 (e.g., gyroscope(s), accelerometer(s), magnetometer(s), etc.) that may sense orientation and/or motion of the UE 200 and provide indications thereof that the processor 210 (e.g., the processor 230 and/or the DSP 231) may be configured to use to determine motion (e.g., a velocity vector and/or an acceleration vector) of the UE 200. The PD 219 may be configured to provide indications of uncertainty and/or error in the determined position and/or motion. Functionality of the PD 219 may be provided in a variety of manners and/or configurations, e.g., by the general purpose/application processor 230, the transceiver 215, the SPS receiver 217, and/or another component of the UE 200, and may be provided by hardware, software, firmware, or various combinations thereof.
Referring also to
The description may refer to the processor 310 performing a function, but this includes other implementations such as where the processor 310 executes software and/or firmware. The description may refer to the processor 310 performing a function as shorthand for one or more of the processors contained in the processor 310 performing the function. The description may refer to the TRP 300 performing a function as shorthand for one or more appropriate components (e.g., the processor 310 and the memory 311) of the TRP 300 (and thus of one of the gNBs 110a, 110b and/or the ng-eNB 114) performing the function. The processor 310 may include a memory with stored instructions in addition to and/or instead of the memory 311. Functionality of the processor 310 is discussed more fully below.
The transceiver 315 may include a wireless transceiver 340 and/or a wired transceiver 350 configured to communicate with other devices through wireless connections and wired connections, respectively. For example, the wireless transceiver 340 may include a wireless transmitter 342 and a wireless receiver 344 coupled to one or more antennas 346 for transmitting (e.g., on one or more uplink channels and/or one or more downlink channels) and/or receiving (e.g., on one or more downlink channels and/or one or more uplink channels) wireless signals 348 and transducing signals from the wireless signals 348 to wired (e.g., electrical and/or optical) signals and from wired (e.g., electrical and/or optical) signals to the wireless signals 348. Thus, the wireless transmitter 342 may include multiple transmitters that may be discrete components or combined/integrated components, and/or the wireless receiver 344 may include multiple receivers that may be discrete components or combined/integrated components. The wireless transceiver 340 may be configured to communicate signals (e.g., with the UE 200, one or more other UEs, and/or one or more other devices) according to a variety of radio access technologies (RATs) such as 5G New Radio (NR), GSM (Global System for Mobiles), UMTS (Universal Mobile Telecommunications System), AMPS (Advanced Mobile Phone System), CDMA (Code Division Multiple Access), WCDMA (Wideband CDMA), LTE (Long-Term Evolution), LTE Direct (LTE-D), 3GPP LTE-V2X (PC5), IEEE 802.11 (including IEEE 802.11p), WiFi, WiFi Direct (WiFi-D), Bluetooth®, Zigbee etc. The wired transceiver 350 may include a wired transmitter 352 and a wired receiver 354 configured for wired communication, e.g., a network interface that may be utilized to communicate with the NG-RAN 135 to send communications to, and receive communications from, the LMF 120, for example, and/or one or more other network entities. The wired transmitter 352 may include multiple transmitters that may be discrete components or combined/integrated components, and/or the wired receiver 354 may include multiple receivers that may be discrete components or combined/integrated components. The wired transceiver 350 may be configured, e.g., for optical communication and/or electrical communication.
The configuration of the TRP 300 shown in
Referring also to
The transceiver 415 may include a wireless transceiver 440 and/or a wired transceiver 450 configured to communicate with other devices through wireless connections and wired connections, respectively. For example, the wireless transceiver 440 may include a wireless transmitter 442 and a wireless receiver 444 coupled to one or more antennas 446 for transmitting (e.g., on one or more downlink channels) and/or receiving (e.g., on one or more uplink channels) wireless signals 448 and transducing signals from the wireless signals 448 to wired (e.g., electrical and/or optical) signals and from wired (e.g., electrical and/or optical) signals to the wireless signals 448. Thus, the wireless transmitter 442 may include multiple transmitters that may be discrete components or combined/integrated components, and/or the wireless receiver 444 may include multiple receivers that may be discrete components or combined/integrated components. The wireless transceiver 440 may be configured to communicate signals (e.g., with the UE 200, one or more other UEs, and/or one or more other devices) according to a variety of radio access technologies (RATs) such as 5G New Radio (NR), GSM (Global System for Mobiles), UMTS (Universal Mobile Telecommunications System), AMPS (Advanced Mobile Phone System), CDMA (Code Division Multiple Access), WCDMA (Wideband CDMA), LTE (Long-Term Evolution), LTE Direct (LTE-D), 3GPP LTE-V2X (PC5), IEEE 802.11 (including IEEE 802.11p), WiFi, WiFi Direct (WiFi-D), Bluetooth®, Zigbee etc. The wired transceiver 450 may include a wired transmitter 452 and a wired receiver 454 configured for wired communication, e.g., a network interface that may be utilized to communicate with the NG-RAN 135 to send communications to, and receive communications from, the TRP 300, for example, and/or one or more other network entities. The wired transmitter 452 may include multiple transmitters that may be discrete components or combined/integrated components, and/or the wired receiver 454 may include multiple receivers that may be discrete components or combined/integrated components. The wired transceiver 450 may be configured, e.g., for optical communication and/or electrical communication.
The description herein may refer to the processor 410 performing a function, but this includes other implementations such as where the processor 410 executes software (stored in the memory 411) and/or firmware. The description herein may refer to the server 400 performing a function as shorthand for one or more appropriate components (e.g., the processor 410 and the memory 411) of the server 400 performing the function.
The configuration of the server 400 shown in
Positioning Techniques
For terrestrial positioning of a UE in cellular networks, techniques such as Advanced Forward Link Trilateration (AFLT) and Observed Time Difference Of Arrival (OTDOA) often operate in “UE-assisted” mode in which measurements of reference signals (e.g., PRS, CRS, etc.) transmitted by base stations are taken by the UE and then provided to a location server. The location server then calculates the position of the UE based on the measurements and known locations of the base stations. Because these techniques use the location server to calculate the position of the UE, rather than the UE itself, these positioning techniques are not frequently used in applications such as car or cell-phone navigation, which instead typically rely on satellite-based positioning.
A UE may use a Satellite Positioning System (SPS) (a Global Navigation Satellite System (GNSS)) for high-accuracy positioning using precise point positioning (PPP) or real time kinematic (RTK) technology. These technologies use assistance data such as measurements from ground-based stations. LTE Release 15 allows the data to be encrypted so that the UEs subscribed to the service exclusively can read the information. Such assistance data varies with time. Thus, a UE subscribed to the service may not easily “break encryption” for other UEs by passing on the data to other UEs that have not paid for the subscription. The passing on would need to be repeated every time the assistance data changes.
In UE-assisted positioning, the UE sends measurements (e.g., TDOA, Angle of Arrival (AoA), etc.) to the positioning server (e.g., LMF/eSMLC). The positioning server has the base station almanac (BSA) that contains multiple ‘entries’ or ‘records’, one record per cell, where each record contains geographical cell location but also may include other data. An identifier of the ‘record’ among the multiple ‘records’ in the BSA may be referenced. The BSA and the measurements from the UE may be used to compute the position of the UE.
In conventional UE-based positioning, a UE computes its own position, thus avoiding sending measurements to the network (e.g., location server), which in turn improves latency and scalability. The UE uses relevant BSA record information (e.g., locations of gNBs (more broadly base stations)) from the network. The BSA information may be encrypted. But since the BSA information varies much less often than, for example, the PPP or RTK assistance data described earlier, it may be easier to make the BSA information (compared to the PPP or RTK information) available to UEs that did not subscribe and pay for decryption keys. Transmissions of reference signals by the gNBs make BSA information potentially accessible to crowd-sourcing or war-driving, essentially enabling BSA information to be generated based on in-the-field and/or over-the-top observations.
Positioning techniques may be characterized and/or assessed based on one or more criteria such as position determination accuracy and/or latency. Latency is a time elapsed between an event that triggers determination of position-related data and the availability of that data at a positioning system interface, e.g., an interface of the LMF 120. At initialization of a positioning system, the latency for the availability of position-related data is called time to first fix (TTFF), and is larger than latencies after the TTFF. An inverse of a time elapsed between two consecutive position-related data availabilities is called an update rate, i.e., the rate at which position-related data are generated after the first fix. Latency may depend on processing capability, e.g., of the UE. For example, a UE may report a processing capability of the UE as a duration of DL PRS symbols in units of time (e.g., milliseconds) that the UE can process every T amount of time (e.g., T ms) assuming 272 PRB (Physical Resource Block) allocation. Other examples of capabilities that may affect latency are a number of TRPs from which the UE can process PRS, a number of PRS that the UE can process, and a bandwidth of the UE.
One or more of many different positioning techniques (also called positioning methods) may be used to determine position of an entity such as one of the UEs 105, 106. For example, known position-determination techniques include RTT, multi-RTT, OTDOA (also called TDOA and including UL-TDOA and DL-TDOA), Enhanced Cell Identification (E-CID), DL-AoD, UL-AoA, etc. RTT uses a time for a signal to travel from one entity to another and back to determine a range between the two entities. The range, plus a known location of a first one of the entities and an angle between the two entities (e.g., an azimuth angle) can be used to determine a location of the second of the entities. In multi-RTT (also called multi-cell RTT), multiple ranges from one entity (e.g., a UE) to other entities (e.g., TRPs) and known locations of the other entities may be used to determine the location of the one entity. In TDOA techniques, the difference in travel times between one entity and other entities may be used to determine relative ranges from the other entities and those, combined with known locations of the other entities may be used to determine the location of the one entity. Angles of arrival and/or departure may be used to help determine location of an entity. For example, an angle of arrival or an angle of departure of a signal combined with a range between devices (determined using signal, e.g., a travel time of the signal, a received power of the signal, etc.) and a known location of one of the devices may be used to determine a location of the other device. The angle of arrival or departure may be an azimuth angle relative to a reference direction such as true north. The angle of arrival or departure may be a zenith angle relative to directly upward from an entity (i.e., relative to radially outward from a center of Earth). E-CID uses the identity of a serving cell, the timing advance (i.e., the difference between receive and transmit times at the UE), estimated timing and power of detected neighbor cell signals, and possibly angle of arrival (e.g., of a signal at the UE from the base station or vice versa) to determine location of the UE. In TDOA, the difference in arrival times at a receiving device of signals from different sources along with known locations of the sources and known offset of transmission times from the sources are used to determine the location of the receiving device.
In a network-centric RTT estimation, the serving base station instructs the UE to scan for/receive RTT measurement signals (e.g., PRS) on serving cells of two or more neighboring base stations (and typically the serving base station, as at least three base stations are needed). The one of more base stations transmit RTT measurement signals on low reuse resources (e.g., resources used by the base station to transmit system information) allocated by the network (e.g., a location server such as the LMF 120). The UE records the arrival time (also referred to as a receive time, a reception time, a time of reception, or a time of arrival (ToA)) of each RTT measurement signal relative to the UE's current downlink timing (e.g., as derived by the UE from a DL signal received from its serving base station), and transmits a common or individual RTT response message (e.g., SRS (sounding reference signal) for positioning, i.e., UL-PRS) to the one or more base stations (e.g., when instructed by its serving base station) and may include the time difference TRx→Tx (i.e., UE TRx−Tx or UERx−Tx) between the ToA of the RTT measurement signal and the transmission time of the RTT response message in a payload of each RTT response message. The RTT response message would include a reference signal from which the base station can deduce the ToA of the RTT response. By comparing the difference TTx→Rx between the transmission time of the RTT measurement signal from the base station and the ToA of the RTT response at the base station to the UE-reported time difference TRx→Tx, the base station can deduce the propagation time between the base station and the UE, from which the base station can determine the distance between the UE and the base station by assuming the speed of light during this propagation time.
A UE-centric RTT estimation is similar to the network-based method, except that the UE transmits uplink RTT measurement signal(s) (e.g., when instructed by a serving base station), which are received by multiple base stations in the neighborhood of the UE. Each involved base station responds with a downlink RTT response message, which may include the time difference between the ToA of the RTT measurement signal at the base station and the transmission time of the RTT response message from the base station in the RTT response message payload.
For both network-centric and UE-centric procedures, the side (network or UE) that performs the RTT calculation typically (though not always) transmits the first message(s) or signal(s) (e.g., RTT measurement signal(s)), while the other side responds with one or more RTT response message(s) or signal(s) that may include the difference between the ToA of the first message(s) or signal(s) and the transmission time of the RTT response message(s) or signal(s).
A multi-RTT technique may be used to determine position. For example, a first entity (e.g., a UE) may send out one or more signals (e.g., unicast, multicast, or broadcast from the base station) and multiple second entities (e.g., other TSPs such as base station(s) and/or UE(s)) may receive a signal from the first entity and respond to this received signal. The first entity receives the responses from the multiple second entities. The first entity (or another entity such as an LMF) may use the responses from the second entities to determine ranges to the second entities and may use the multiple ranges and known locations of the second entities to determine the location of the first entity by trilateration.
In some instances, additional information may be obtained in the form of an angle of arrival (AoA) or angle of departure (AoD) that defines a straight-line direction (e.g., which may be in a horizontal plane or in three dimensions) or possibly a range of directions (e.g., for the UE from the locations of base stations). The intersection of two directions can provide another estimate of the location for the UE.
For positioning techniques using PRS (Positioning Reference Signal) signals (e.g., TDOA and RTT), PRS signals sent by multiple TRPs are measured and the arrival times of the signals, known transmission times, and known locations of the TRPs used to determine ranges from a UE to the TRPs. For example, an RSTD (Reference Signal Time Difference) may be determined for PRS signals received from multiple TRPs and used in a TDOA technique to determine position (location) of the UE. A positioning reference signal may be referred to as a PRS or a PRS signal. The PRS signals are typically sent using the same power and PRS signals with the same signal characteristics (e.g., same frequency shift) may interfere with each other such that a PRS signal from a more distant TRP may be overwhelmed by a PRS signal from a closer TRP such that the signal from the more distant TRP may not be detected. PRS muting may be used to help reduce interference by muting some PRS signals (reducing the power of the PRS signal, e.g., to zero and thus not transmitting the PRS signal). In this way, a weaker (at the UE) PRS signal may be more easily detected by the UE without a stronger PRS signal interfering with the weaker PRS signal. The term RS, and variations thereof (e.g., PRS, SRS, CSI-RS ((Channel State Information-Reference Signal)), may refer to one reference signal or more than one reference signal.
Positioning reference signals (PRS) include downlink PRS (DL PRS, often referred to simply as PRS) and uplink PRS (UL PRS) (which may be called SRS (Sounding Reference Signal) for positioning). A PRS may comprise a PN code (pseudorandom number code) or be generated using a PN code (e.g., by modulating a carrier signal with the PN code) such that a source of the PRS may serve as a pseudo-satellite (a pseudolite). The PN code may be unique to the PRS source (at least within a specified area such that identical PRS from different PRS sources do not overlap). PRS may comprise PRS resources or PRS resource sets of a frequency layer. A DL PRS positioning frequency layer (or simply a frequency layer) is a collection of DL PRS resource sets, from one or more TRPs, with PRS resource(s) that have common parameters configured by higher-layer parameters DL-PRS-PositioningFrequencyLayer, DL-PRS-ResourceSet, and DL-PRS-Resource. Each frequency layer has a DL PRS subcarrier spacing (SCS) for the DL PRS resource sets and the DL PRS resources in the frequency layer. Each frequency layer has a DL PRS cyclic prefix (CP) for the DL PRS resource sets and the DL PRS resources in the frequency layer. In 5G, a resource block occupies 12 consecutive subcarriers and a specified number of symbols. Also, a DL PRS Point A parameter defines a frequency of a reference resource block (and the lowest subcarrier of the resource block), with DL PRS resources belonging to the same DL PRS resource set having the same Point A and all DL PRS resource sets belonging to the same frequency layer having the same Point A. A frequency layer also has the same DL PRS bandwidth, the same start PRB (and center frequency), and the same value of comb size (i.e., a frequency of PRS resource elements per symbol such that for comb-N, every Nth resource element is a PRS resource element). A PRS resource set is identified by a PRS resource set ID and may be associated with a particular TRP (identified by a cell ID) transmitted by an antenna panel of a base station. A PRS resource ID in a PRS resource set may be associated with an omnidirectional signal, and/or with a single beam (and/or beam ID) transmitted from a single base station (where a base station may transmit one or more beams). Each PRS resource of a PRS resource set may be transmitted on a different beam and as such, a PRS resource, or simply resource can also be referred to as a beam. This does not have any implications on whether the base stations and the beams on which PRS are transmitted are known to the UE.
A TRP may be configured, e.g., by instructions received from a server and/or by software in the TRP, to send DL PRS per a schedule. According to the schedule, the TRP may send the DL PRS intermittently, e.g., periodically at a consistent interval from an initial transmission. The TRP may be configured to send one or more PRS resource sets. A resource set is a collection of PRS resources across one TRP, with the resources having the same periodicity, a common muting pattern configuration (if any), and the same repetition factor across slots. Each of the PRS resource sets comprises multiple PRS resources, with each PRS resource comprising multiple Resource Elements (REs) that may be in multiple Resource Blocks (RBs) within N (one or more) consecutive symbol(s) within a slot. An RB is a collection of REs spanning a quantity of one or more consecutive symbols in the time domain and a quantity (12 for a 5G RB) of consecutive sub-carriers in the frequency domain. Each PRS resource is configured with an RE offset, slot offset, a symbol offset within a slot, and a number of consecutive symbols that the PRS resource may occupy within a slot. The RE offset defines the starting RE offset of the first symbol within a DL PRS resource in frequency. The relative RE offsets of the remaining symbols within a DL PRS resource are defined based on the initial offset. The slot offset is the starting slot of the DL PRS resource with respect to a corresponding resource set slot offset. The symbol offset determines the starting symbol of the DL PRS resource within the starting slot. Transmitted REs may repeat across slots, with each transmission being called a repetition such that there may be multiple repetitions in a PRS resource. The DL PRS resources in a DL PRS resource set are associated with the same TRP and each DL PRS resource has a DL PRS resource ID. A DL PRS resource ID in a DL PRS resource set is associated with a single beam transmitted from a single TRP (although a TRP may transmit one or more beams).
A PRS resource may also be defined by quasi-co-location and start PRB parameters. A quasi-co-location (QCL) parameter may define any quasi-co-location information of the DL PRS resource with other reference signals. The DL PRS may be configured to be QCL type D with a DL PRS or SS/PBCH (Synchronization Signal/Physical Broadcast Channel) Block from a serving cell or a non-serving cell. The DL PRS may be configured to be QCL type C with an SS/PBCH Block from a serving cell or a non-serving cell. The start PRB parameter defines the starting PRB index of the DL PRS resource with respect to reference Point A. The starting PRB index has a granularity of one PRB and may have a minimum value of 0 and a maximum value of 2176 PRBs.
A PRS resource set is a collection of PRS resources with the same periodicity, same muting pattern configuration (if any), and the same repetition factor across slots. Every time all repetitions of all PRS resources of the PRS resource set are configured to be transmitted is referred as an “instance”. Therefore, an “instance” of a PRS resource set is a specified number of repetitions for each PRS resource and a specified number of PRS resources within the PRS resource set such that once the specified number of repetitions are transmitted for each of the specified number of PRS resources, the instance is complete. An instance may also be referred to as an “occasion.” A DL PRS configuration including a DL PRS transmission schedule may be provided to a UE to facilitate (or even enable) the UE to measure the DL PRS.
Multiple frequency layers of PRS may be aggregated to provide an effective bandwidth that is larger than any of the bandwidths of the layers individually. Multiple frequency layers of component carriers (which may be consecutive and/or separate) and meeting criteria such as being quasi co-located (QCLed), and having the same antenna port, may be stitched to provide a larger effective PRS bandwidth (for DL PRS and UL PRS) resulting in increased time of arrival measurement accuracy. Stitching comprises combining PRS measurements over individual bandwidth fragments into a unified piece such that the stitched PRS may be treated as having been taken from a single measurement. Being QCLed, the different frequency layers behave similarly, enabling stitching of the PRS to yield the larger effective bandwidth. The larger effective bandwidth, which may be referred to as the bandwidth of an aggregated PRS or the frequency bandwidth of an aggregated PRS, provides for better time-domain resolution (e.g., of TDOA). An aggregated PRS includes a collection of PRS resources and each PRS resource of an aggregated PRS may be called a PRS component, and each PRS component may be transmitted on different component carriers, bands, or frequency layers, or on different portions of the same band.
RTT positioning is an active positioning technique in that RTT uses positioning signals sent by TRPs to UEs and by UEs (that are participating in RTT positioning) to TRPs. The TRPs may send DL-PRS signals that are received by the UEs and the UEs may send SRS (Sounding Reference Signal) signals that are received by multiple TRPs. A sounding reference signal may be referred to as an SRS or an SRS signal. In 5G multi-RTT, coordinated positioning may be used with the UE sending a single UL-SRS for positioning that is received by multiple TRPs instead of sending a separate UL-SRS for positioning for each TRP. A TRP that participates in multi-RTT will typically search for UEs that are currently camped on that TRP (served UEs, with the TRP being a serving TRP) and also UEs that are camped on neighboring TRPs (neighbor UEs). Neighbor TRPs may be TRPs of a single BTS (e.g., gNB), or may be a TRP of one BTS and a TRP of a separate BTS. For RTT positioning, including multi-RTT positioning, the DL-PRS signal and the UL-SRS for positioning signal in a PRS/SRS for positioning signal pair used to determine RTT (and thus used to determine range between the UE and the TRP) may occur close in time to each other such that errors due to UE motion and/or UE clock drift and/or TRP clock drift are within acceptable limits. For example, signals in a PRS/SRS for positioning signal pair may be transmitted from the TRP and the UE, respectively, within about 10 ms of each other. With SRS for positioning signals being sent by UEs, and with PRS and SRS for positioning signals being conveyed close in time to each other, it has been found that radio-frequency (RF) signal congestion may result (which may cause excessive noise, etc.) especially if many UEs attempt positioning concurrently and/or that computational congestion may result at the TRPs that are trying to measure many UEs concurrently.
RTT positioning may be UE-based or UE-assisted. In UE-based RTT, the UE 200 determines the RTT and corresponding range to each of the TRPs 300 and the position of the UE 200 based on the ranges to the TRPs 300 and known locations of the TRPs 300. In UE-assisted RTT, the UE 200 measures positioning signals and provides measurement information to the TRP 300, and the TRP 300 determines the RTT and range. The TRP 300 provides ranges to a location server, e.g., the server 400, and the server determines the location of the UE 200, e.g., based on ranges to different TRPs 300. The RTT and/or range may be determined by the TRP 300 that received the signal(s) from the UE 200, by this TRP 300 in combination with one or more other devices, e.g., one or more other TRPs 300 and/or the server 400, or by one or more devices other than the TRP 300 that received the signal(s) from the UE 200.
Various positioning techniques are supported in 5G NR. The NR native positioning methods supported in 5G NR include DL-only positioning methods, UL-only positioning methods, and DL+UL positioning methods. Downlink-based positioning methods include DL-TDOA and DL-AoD. Uplink-based positioning methods include UL-TDOA and UL-AoA. Combined DL+UL-based positioning methods include RTT with one base station and RTT with multiple base stations (multi-RTT).
A position estimate (e.g., for a UE) may be referred to by other names, such as a location estimate, location, position, position fix, fix, or the like. A position estimate may be geodetic and comprise coordinates (e.g., latitude, longitude, and possibly altitude) or may be civic and comprise a street address, postal address, or some other verbal description of a location. A position estimate may further be defined relative to some other known location or defined in absolute terms (e.g., using latitude, longitude, and possibly altitude). A position estimate may include an expected error or uncertainty (e.g., by including an area or volume within which the location is expected to be included with some specified or default level of confidence).
Selective Symbol Measurement
Referring to
The description herein may refer to the processor 510 performing a function, but this includes other implementations such as where the processor 510 executes software (stored in the memory 530) and/or firmware. The description herein may refer to the UE 500 performing a function as shorthand for one or more appropriate components (e.g., the processor 510 and the memory 530) of the UE 500 performing the function. The processor 510 (possibly in conjunction with the memory 530 and, as appropriate, the interface 520) includes a symbol selection unit 550. The configuration and functionality of the symbol selection unit 550 is discussed further herein, with the symbol selection unit 550 being configured to perform the functionality described as being performed by the symbol selection unit 550.
Referring also to
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The UE 500 may stay awake from the first symbol measured to the last symbol measured in each respective combination. For example, the UE 500 may not wake before the first symbol in a measurement combination, may not remain awake after the last symbol in a measurement combination, and may stay awake between non-consecutive symbols (as going to sleep between non-consecutive symbols to be measured may not be practical for the UE 500). For the comb-12 schedule of the entry 951, all 12 symbols are measured, and thus the UE 500 is awake for 12 symbols. For the effective single-symbol comb-6 schedule of the entry 952, two-symbol measurements are made by measuring any of the two-symbol combinations indicated in the field 920. The UE 500 may be awake for as little as two symbols, and thus may save 10 symbols relative to the 12-symbol schedule, as indicated in the field 940 of the entry 952. For the effective single-symbol comb-3 schedule of the entry 953, four-symbol measurements are made by measuring any of the four-symbol combinations indicated in the field 920. The UE 500 may be awake for as little as four symbols, and thus may save eight symbols relative to the 12-symbol schedule, as indicated in the field 940 of the entry 953. For the effective single-symbol comb-4 schedule of the entry 954, three-symbol measurements are made by measuring any of the three-symbol combinations indicated in the field 920. The UE 500 may be awake for eight symbols in order to measure the three symbols in each combination because the measured symbols, in order to achieve uniform frequency spacing, are not consecutive in the time domain. Thus, the UE 500 may save four symbols relative to the 12-symbol schedule, as indicated in the field 940 of the entry 954. The number of saved symbols corresponds to processing, and processing power, saved by measuring, and otherwise processing, fewer symbols relative to processing a fully-staggered combination of symbols. The saved symbols correspond to less-than-fully-staggered combinations of symbols, with corresponding multi-peak time-domain SNR plots (e.g., as shown in
Referring also to
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Referring to
The symbol selection unit 550 may be configured to respond to one or more triggers to implement, or to determine whether to implement, selective signal (e.g., selective symbol) measurement. For example, a trigger may be a stored energy level of a battery of the UE 500 dropping below a threshold value, e.g., in combination with expected power consumption. For example, the trigger may be that the symbol selection unit 550 determines that an expected battery life, e.g., an expected amount of time until the battery drops below a threshold level (e.g., 2% of capacity) is less than a threshold amount of time. Another example trigger is an instruction, received by the UE 500 via the interface 520, to implement selective signal measurement. Another example trigger is an increase in expected power consumption by the UE 500, e.g., due to an increase in expected signals to measure, an increase in expected performance of calculations and/or other functions. Another example trigger is movement of the UE 500 closer to a TRP 300. The symbol selection unit 550 may be configured to respond to determining that the UE 500 is moving (as indicated by a velocity vector 1660) nearer to a TRP, e.g., a TRP 1640 shown in
The symbol selection unit 550 may be configured to analyze one or more factors to determine whether, and if so how, to selectively measure one or more signals, e.g., to reduce signal measurements relative to past and/or expected measurements. Multiple factors may be considered in concert, e.g., using a weighted formula such that different factors may have different weights (different amounts of influence on a decision regarding selective signal measurement). Example factors include desired power/processing use or saving, potential power/processing saving, positioning session type (e.g., emergency, non-emergency), RSRP, RSRQ, SNR, SINR (signal-to-interference-and-noise ratio), ToA/RSTD accuracy, a periodicity of PRS occasions, UE movement, Doppler measurement(s), delay spread, bandwidth of RE(s) to be measured, movement (e.g., velocity) of the UE 500 (e.g., relative to a base station), scheduled power consumption, potential power consumption (e.g., potential power reduction compared to a reference, e.g., current processing rate), separation of aliased peaks of one or more signal measurement options, expected battery life, desired battery life, scheduled battery use, content of a power reduction instructions, and confidence in meeting one or more quality of service metrics. One or more other factors may also or alternatively be considered by the symbol selection unit 550.
The symbol selection unit 550 may determine whether to selectively measure a reference signal and/or a selective measurement configuration to use in order to satisfy one or more performance requirements (e.g., boundary conditions). For example, if multiple options are available that satisfy the requirement(s), then the symbol selection unit 550 may select the option with the most symbol savings (the least amount of symbols for which the UE 500 is awake). Numerous examples of requirements or combinations of requirements may be used. For example, a requirement may be that a number of symbols over which the UE 500 will be awake will meet a desired power consumption (e.g., a power consumption reduction of more than a threshold amount relative to a present or expected power consumption rate, or power consumption below a threshold power consumption). A combination of requirements may be that the selected measurement configuration saves at least a threshold number of symbols to meet a desired power consumption and also allows one or more performance metrics (e.g., ToA/RSTD accuracy, RSRP, RSRQ, SNR) to be met. As another example, the symbol selection unit 550 may select a measurement configuration that will allow an SNR, RSRP, or RSRQ metric (or combination thereof) to be met and allow the UE 500 to decode the ToA using less than all (e.g., possibly half or less) of a symbol. A requirement may be a minimum distance between SNR time-domain peaks. Other requirements may be a maximum delay spread, a minimum bandwidth covered by measured REs, a maximum number of SNR time-domain peaks, a maximum number of symbols for the UE 500 to be awake for, a maximum comb number, and/or a confidence that the UE 500 can identify the correct time-domain SNR peak (which may be determined from one or more of the factors considered). For example, higher delay spread and lower bandwidth of measured REs may both widen SNR peaks and thus an upper limit may be placed on delay spread and/or a lower limit placed on bandwidth of the REs measured.
Selective symbol measurement may be limited in duration. For example, the symbol selection unit 550 may terminate selective symbol measurement in response to one or more factors. Examples of such factors include, but are not limited to: the UE 500 receiving charging energy; a battery level of the UE 500 exceeding a threshold level; a change in expected power consumption by the UE 500; an instruction to terminate selective measurement; an expiration of a time (e.g., for which the UE 500 was instructed to implement selective measurement, or a default time window used by the UE 500 when selective measurement is implemented, etc.); a change in one or more of the performance requirements based on which selective measurement was implemented; a change in motion of the UE 500 (from nearing a TRP 300 to moving away from the TRP 300); a change in measured delay spread; a change in serving cell; a change in PRS configuration; a change in transmit beam; etc.
Referring also to
At stage 1710, the TRP 300 sends a PRS configuration message 1712 to the UE 500. The PRS configuration message 1712 includes parameters defining the PRS and provides scheduling information for scheduled transmission of PRS to the UE 500.
At stage 1720, the TRP 300 may send PRS 1722 to the UE 500. The PRS 1722 is sent in accordance with the parameters and schedule provided in the PRS configuration message 1712. Stage 1720 is optional, as the UE 500 may initiate and/or determine selective PRS measurement without having first received and measured PRS.
At stage 1730, the UE 500, e.g., the symbol selection unit 550, is triggered to determine whether, and if so, how, to implement selective PRS measurement. For example, the TRP 300 may send a selective measurement trigger 1732 to the UE 500. The selective measurement trigger may instruct the UE 500 to determine whether to implement selective PRS measurement. Alternatively, the selective measurement trigger may instruct the UE 500 to implement selective PRS measurement, and may provide one or more performance requirements for the selective measurement. At substage 1734, the UE 500, e.g., the symbol selection unit 550, may initiate selective measurement determination, e.g., in response to receiving the selective measurement trigger 1732 and/or in response to one or more trigger conditions determined by the UE 500. If selective symbol measurement is determined to be desired, then the symbol selection unit 550 attempts to determine a selective measurement configuration to implement. The selective measurement configuration selected may be based on measurement of the PRS 1722, if the PRS 1722 was sent by the TRP 300 and measured by the UE 500. The symbol selection unit 550 may send a PRS configuration request 1736 to the TRP 300 for a specific configuration of PRS. For example, the scheduled PRS may have the transmission schedule 800 and the symbol selection unit 550 may determine that an effective single-symbol comb-4 measurement schedule is desired, and that more than four symbols are desired to be saved. The symbol selection unit 550 may respond to these conditions (the transmission schedule and the performance metrics) by requesting that the TRP 300 use the transmission schedule 1000 for the PRS such that the UE 500 may meet the desired performance metrics. The PRS configuration request 1736 may request a specific PRS transmission schedule, or may request a new transmission schedule generally, or may request a new schedule with one or more specified characteristics (e.g., comb number).
At stage 1740, the TRP 300 sends PRS 1742 to the UE 500. The PRS 1742 may be sent in accordance with the originally-scheduled PRS transmission schedule or a new PRS transmission schedule in response to the PRS configuration request 1736.
At stage 1750, the UE 500 implements the determined selective measurement configuration. The symbol selection unit 550 selects the symbol(s) according to the selective measurement configuration determined at substage 1734, and measures those symbols. The symbol selection unit 550 wakes the UE 500 up from a sleep mode, in which the UE 500 does not listen for or measure symbols of the PRS 1742, into a wake mode during which the UE 500 listens for and measures the symbols of the PRS 1742.
At stage 1760, the UE determines position information. The position information may include, for example, one or more measurements, one or more ranges, and/or one or more position estimates for the UE 500. The UE 500 may send a position information message 1762 to the TRP 300 (and/or to the server 400) as appropriate (e.g., for the TRP 300 and/or the server 400 (e.g., an LMF) to determine a position estimate of the UE 500).
Operation
Referring to
At stage 1810, the method 1800 includes selecting a symbol subset of a symbol group of the OFDM PRS, the OFDM PRS comprising a slot of symbols comprising the symbol group, the symbol group consisting of a first symbol quantity of consecutive ones of the symbols, the symbol group being fully staggered in frequency domain, the symbol subset consisting of a second symbol quantity of the symbols of the symbol group, the second symbol quantity being smaller than the first symbol quantity, and the symbol subset being less than fully staggered in the frequency domain. For example, the symbol selection unit 550 selects a symbol subset, e.g., by determining a symbol combination (e.g., a symbols aggregated combination as shown in
At stage 1820, the method 1800 includes measuring the symbol subset without measuring all of the symbols of the symbol group. For example, as discussed with respect to stage 1750 and
Implementations of the method 1800 may include one or more of the following features. In an example implementation, subcarriers of the symbol subset are uniformly spaced in the frequency domain. In another example implementation, the symbol subset comprises at least two consecutive symbols of the symbol group. For example, the symbol group includes at least two consecutive symbols and may include one or more other symbols. In another example implementation, the symbol subset is selected based on at least one of a desired processing reduction or a desired power consumption reduction. The desired power consumption reduction may be based on a present power consumption rate and/or an expected (e.g., scheduled) power consumption rate (i.e., power consumption rate based on scheduled processing). The desired reduction may be, for example, a reduction amount to meet a desired extension of battery life. In another example implementation, the symbol subset is selected based on a third symbol quantity of consecutive ones of the symbols that include all symbols of the symbol subset, the third symbol quantity being smaller than the first symbol quantity. For example, the UE 500 may wake up for more symbols than are in the symbol subset (e.g., if the symbols in the symbol subset are not consecutive (in time)). The symbol selection unit 550 may select the symbol subset based on the number of symbols for which the UE 500 will be awake, e.g., instead of or not just based on the number of symbols in the symbol subset. In another example implementation, the slot is a second slot, the OFDM PRS comprises a first slot comprising the symbol group, and the method 1800 includes obtaining a measurement of the symbol group of the first slot, wherein the symbol subset is selected based on a metric of the measurement. The metric of measurement may include, for example, a Doppler measurement, a delay spread, an RSRP, an RSRQ, and/or an SNR, etc. The processor 510, possibly in combination with the memory 530, possibly in combination with the interface 520 (e.g., the wireless receiver 244 and the antenna 246) may comprise means for obtaining a measurement of the symbol group. In a further example implementation, the method 1800 includes decoding a time of arrival (ToA) of the OFDM PRS at the user equipment, where the symbol subset is selected based on the metric of the measurement meeting a corresponding threshold quality and the time of arrival being able to be decoded by the user equipment using less than all (e.g., possibly half or less) of a symbol of the OFDM PRS. For example, the symbol selection unit 550 may select the symbol subset based on an SNR, RSRP, and/or RSRQ of the symbol group and an RSTD accuracy, determined from decoding the ToA from a portion of a symbol (that is less than all of the symbol), being at least as good as a threshold accuracy. If the ToA can be decoded using (1/N)th of a symbol, then the UE 500 likely can have a subset of symbols that result in an effective comb-N in the frequency domain while being able to meet a desired QoS. The threshold accuracy may be, for example, a threshold value of a main peak power divided by a noise floor power, or the main peak power divided by a median power. The processor 510, possibly in combination with the memory 530, possibly in combination with the interface 520 (e.g., the wireless receiver 244 and the antenna 246) may comprise means for decoding the ToA.
Also or alternatively, implementations of the method 1800 may include one or more of the following features. In an example implementation, the symbol subset is selected in response to an indication that the user equipment is nearing a source of the OFDM PRS. For example, the symbol selection unit 550 may determine and select a symbol combination with fewer symbols than presently measured (e.g., a fully-staggered set of symbols or a less-than-fully-staggered set of symbols) based on the UE 500 reducing a distance between the UE 500 and a TRP 300. Thus, the UE 500 may already be measuring a reduced-set of symbols and the symbol selection unit 550 may further reduce the number of symbols selectively measured to further reduce power consumption and/or processing resources. In another example implementation, the symbol subset is first symbol subset, and the method 1800 includes selecting a second symbol subset of the symbol group in response to an indication that the user equipment is moving away from a source of the OFDM PRS, the second symbol subset consisting of a fourth symbol quantity of the symbols of the symbol group, the fourth symbol quantity being bigger than the second symbol quantity, the second symbol subset being less than fully staggered. For example, the symbol selection unit 550 may determine a symbol combination with more symbols than are presently being measured based on the UE 500 increasing a distance between the UE 500 and a TRP 300, e.g., to improve performance (e.g., measurement accuracy). In another example implementation, the symbol subset is selected based on a time between occasions of the OFDM PRS. For example, if PRS occasions are closely spaced in time (e.g., 100 ms from the beginning of one occasion to the beginning of the next occasion), then the symbol selection unit 550 may select a symbol subset that is smaller and/or have a higher effective single-symbol comb number than if the PRS occasions are spaced further apart (e.g., to reduce power consumption and/or processing resources while achieving acceptable performance). In another example implementation, the symbol subset is selected based on motion of the user equipment. For example, the symbol selection unit 550 may select the symbol subset to have a lower effective single-symbol comb number the faster the UE 500 is moving, or the more the UE 500 moves between PRS occasions (e.g., using PRS occasion spacing and speed together to select the symbol subset) in order to achieve desired performance (e.g., measurement accuracy) while the UE is in motion. In another example implementation, the symbol subset is selected based on a bandwidth of the symbol subset. The symbol selection unit 550 may select the symbol subset to be as small as possible while maintaining a threshold confidence that the UE 500 can identify the correct SNR peak in view of the widening of the SNR peaks as the bandwidth of the symbol subset decreases.
Implementation Examples
Implementation examples are provided in the following numbered clauses.
Clause 1. A user equipment comprising:
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- a receiver configured to receive a wireless orthogonal frequency division multiplexed (OFDM) positioning reference signal (PRS);
- a memory; and
- a processor, communicatively coupled to the receiver and the memory, configured to:
- select a symbol subset of a symbol group of the OFDM PRS, the OFDM PRS comprising a slot of symbols comprising the symbol group, the symbol group consisting of a first symbol quantity of consecutive ones of the symbols, the symbol group being fully staggered in frequency domain, the symbol subset consisting of a second symbol quantity of the symbols of the symbol group, the second symbol quantity being smaller than the first symbol quantity, and the symbol subset being less than fully staggered in the frequency domain; and
- measure the symbol subset without measuring all of the symbols of the symbol group.
Clause 2. The user equipment of clause 1, wherein subcarriers of the symbol subset are uniformly spaced in the frequency domain.
Clause 3. The user equipment of clause 1, wherein the symbol subset comprises at least two consecutive symbols of the symbol group.
Clause 4. The user equipment of clause 1, wherein the processor is configured to select the symbol subset based on at least one of a desired processing reduction or a desired power consumption reduction.
Clause 5. The user equipment of clause 1, wherein the processor is configured to select the symbol subset based on a third symbol quantity of consecutive ones of the symbols that include all symbols of the symbol subset, the third symbol quantity being smaller than the first symbol quantity.
Clause 6. The user equipment of clause 1, wherein the slot is a second slot, the OFDM PRS comprises a first slot comprising the symbol group, and wherein the processor is configured to obtain a measurement of the symbol group of the first slot and to select the symbol subset based on a metric of the measurement.
Clause 7. The user equipment of clause 6, wherein the processor is configured to select the symbol subset based on the metric of the measurement meeting a corresponding threshold quality and the processor being able to decode a time of arrival of the OFDM PRS using less than all of a symbol of the OFDM PRS.
Clause 8. The user equipment of clause 1, wherein the processor is configured to select the symbol subset in response to an indication that the user equipment is nearing a source of the OFDM PRS.
Clause 9. The user equipment of clause 1, wherein the symbol subset is a first symbol subset, and wherein the processor is configured to select a second symbol subset of the symbol group in response to an indication that the user equipment is moving away from a source of the OFDM PRS, the second symbol subset consisting of a fourth symbol quantity of the symbols of the symbol group, the fourth symbol quantity being bigger than the second symbol quantity, and the second symbol subset being less than fully staggered in the frequency domain.
Clause 10. The user equipment of clause 1, wherein the processor is configured to select the symbol subset based on a time between occasions of the OFDM PRS.
Clause 11. The user equipment of clause 1, wherein the processor is configured to select the symbol subset based on motion of the user equipment.
Clause 12. The user equipment of clause 1, wherein the processor is configured to select the symbol subset based on a bandwidth of the symbol subset.
Clause 13. A method of measuring a wireless orthogonal frequency division multiplexed (OFDM) positioning reference signal (PRS) at a user equipment, the method comprising:
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- selecting a symbol subset of a symbol group of the OFDM PRS, the OFDM PRS comprising a slot of symbols comprising the symbol group, the symbol group consisting of a first symbol quantity of consecutive ones of the symbols, the symbol group being fully staggered in frequency domain, the symbol subset consisting of a second symbol quantity of the symbols of the symbol group, the second symbol quantity being smaller than the first symbol quantity, and the symbol subset being less than fully staggered in the frequency domain; and
- measuring the symbol subset without measuring all of the symbols of the symbol group.
Clause 14. The method of clause 13, wherein subcarriers of the symbol subset are uniformly spaced in the frequency domain.
Clause 15. The method of clause 13, wherein the symbol subset comprises at least two consecutive symbols of the symbol group.
Clause 16. The method of clause 13, wherein the symbol subset is selected based on at least one of a desired processing reduction or a desired power consumption reduction.
Clause 17. The method of clause 13, wherein the symbol subset is selected based on a third symbol quantity of consecutive ones of the symbols that include all symbols of the symbol subset, the third symbol quantity being smaller than the first symbol quantity.
Clause 18. The method of clause 13, wherein the slot is a second slot, the OFDM PRS comprises a first slot comprising the symbol group, and the method further comprises obtaining a measurement of the symbol group of the first slot, wherein the symbol subset is selected based on a metric of the measurement.
Clause 19. The method of clause 18, further comprising decoding a time of arrival of the OFDM PRS at the user equipment, wherein the symbol subset is selected based on the metric of the measurement meeting a corresponding threshold quality and the time of arrival being able to be decoded by the user equipment using less than all of a symbol of the OFDM PRS.
Clause 20. The method of clause 13, wherein the symbol subset is selected in response to an indication that the user equipment is nearing a source of the OFDM PRS.
Clause 21. The method of clause 13, wherein the symbol subset is a first symbol subset, and wherein the method further comprises selecting a second symbol subset of the symbol group in response to an indication that the user equipment is moving away from a source of the OFDM PRS, the second symbol subset consisting of a fourth symbol quantity of the symbols of the symbol group, the fourth symbol quantity being bigger than the second symbol quantity, and the second symbol subset being less than fully staggered in the frequency domain.
Clause 22. The method of clause 13, wherein the symbol subset is selected based on a time between occasions of the OFDM PRS.
Clause 23. The method of clause 13, wherein the symbol subset is selected based on motion of the user equipment.
Clause 24. The method of clause 13, wherein the symbol subset is selected based on a bandwidth of the symbol subset.
Clause 25. A user equipment comprising:
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- means for receiving a wireless orthogonal frequency division multiplexed (OFDM) positioning reference signal (PRS);
- means for selecting a symbol subset of a symbol group of the OFDM PRS, the OFDM PRS comprising a slot of symbols comprising the symbol group, the symbol group consisting of a first symbol quantity of consecutive ones of the symbols, the symbol group being fully staggered in frequency domain, the symbol subset consisting of a second symbol quantity of the symbols of the symbol group, the second symbol quantity being smaller than the first symbol quantity, and the symbol subset being less than fully staggered in the frequency domain; and
- means for measuring the symbol subset without measuring all of the symbols of the symbol group.
Clause 26. The user equipment of clause 25, wherein subcarriers of the symbol subset are uniformly spaced in the frequency domain.
Clause 27. The user equipment of clause 25, wherein the symbol subset comprises at least two consecutive symbols of the symbol group.
Clause 28. The user equipment of clause 25, wherein the means for selecting the symbol subset include means for selecting the symbol subset based on at least one of a desired processing reduction or a desired power consumption reduction.
Clause 29. The user equipment of clause 25, wherein the means for selecting the symbol subset include means for selecting the symbol subset based on a third symbol quantity of consecutive ones of the symbols that include all symbols of the symbol subset, the third symbol quantity being smaller than the first symbol quantity.
Clause 30. The user equipment of clause 25, wherein the slot is a second slot, the OFDM PRS comprises a first slot comprising the symbol group, and the user equipment further comprises means for obtaining a measurement of the symbol group of the first slot, wherein the means for selecting the symbol subset include means for selecting select the symbol subset based on a metric of the measurement.
Clause 31. The user equipment of clause 30, further comprising means for decoding a time of arrival of the OFDM PRS, wherein the means for selecting the symbol subset include means for selecting the symbol subset based on the metric of the measurement meeting a corresponding threshold quality and the means for decoding the time of arrival being able to decode the time of arrival of the OFDM PRS using less than all of a symbol of the OFDM PRS.
Clause 32. The user equipment of clause 25, wherein the means for selecting the symbol subset include means for selecting the symbol subset in response to an indication that the user equipment is nearing a source of the OFDM PRS.
Clause 33. The user equipment of clause 25, wherein the symbol subset is a first symbol subset, the user equipment further comprising means for selecting a second symbol subset of the symbol group in response to an indication that the user equipment is moving away from a source of the OFDM PRS, the second symbol subset consisting of a fourth symbol quantity of the symbols of the symbol group, the fourth symbol quantity being bigger than the second symbol quantity, and the second symbol subset being less than fully staggered in the frequency domain.
Clause 34. The user equipment of clause 25, wherein the means for selecting the symbol subset include means for selecting the symbol subset based on a time between occasions of the OFDM PRS.
Clause 35. The user equipment of clause 25, wherein the means for selecting the symbol subset include means for selecting the symbol subset based on motion of the user equipment.
Clause 36. The user equipment of clause 25, wherein the means for selecting the symbol subset include means for selecting the symbol subset based on a bandwidth of the symbol subset.
Clause 37. A non-transitory, processor-readable storage medium comprising processor-readable instructions configured to cause a processor of a user equipment, in order to measure a wireless orthogonal frequency division multiplexed (OFDM) positioning reference signal (PRS), to:
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- select a symbol subset of a symbol group of the OFDM PRS, the OFDM PRS comprising a slot of symbols comprising the symbol group, the symbol group consisting of a first symbol quantity of consecutive ones of the symbols, the symbol group being fully staggered in frequency domain, the symbol subset consisting of a second symbol quantity of the symbols of the symbol group, the second symbol quantity being smaller than the first symbol quantity, and the symbol subset being less than fully staggered in the frequency domain; and
- measure the symbol subset without measuring all of the symbols of the symbol group.
Clause 38. The storage medium of clause 37, wherein subcarriers of the symbol subset are uniformly spaced in the frequency domain.
Clause 39. The storage medium of clause 37, wherein the symbol subset comprises at least two consecutive symbols of the symbol group.
Clause 40. The storage medium of clause 37, wherein the processor-readable instructions configured to cause the processor to select the symbol subset include processor-readable instructions configured to cause the processor to select the symbol subset based on at least one of a desired processing reduction or a desired power consumption reduction.
Clause 41. The storage medium of clause 37, wherein the processor-readable instructions configured to cause the processor to select the symbol subset include processor-readable instructions configured to cause the processor to select the symbol subset based on a third symbol quantity of consecutive ones of the symbols that include all symbols of the symbol subset, the third symbol quantity being smaller than the first symbol quantity.
Clause 42. The storage medium of clause 37, wherein the slot is a second slot, the OFDM PRS comprises a first slot comprising the symbol group, and the storage medium further comprises processor-readable instructions configured to cause the processor to obtain a measurement of the symbol group of the first slot, wherein the processor-readable instructions configured to cause the processor to select the symbol subset include processor-readable instructions configured to cause the processor to select the symbol subset based on a metric of the measurement.
Clause 43. The storage medium of clause 42, further comprising processor-readable instructions configured to cause the processor to decode a time of arrival of the OFDM PRS at the user equipment, wherein the processor-readable instructions configured to cause the processor to select the symbol subset include processor-readable instructions configured to cause the processor to select the symbol subset based on the metric of the measurement meeting a corresponding threshold quality and the time of arrival being able to be decoded by the processor using less than all of a symbol of the OFDM PRS.
Clause 44. The storage medium of clause 37, wherein the processor-readable instructions configured to cause the processor to select the symbol subset include processor-readable instructions configured to cause the processor to select the symbol subset in response to an indication that the user equipment is nearing a source of the OFDM PRS.
Clause 45. The storage medium of clause 37, wherein the symbol subset is a first symbol subset, and wherein the storage medium further comprises processor-readable instructions configured to cause the processor to select a second symbol subset of the symbol group in response to an indication that the user equipment is moving away from a source of the OFDM PRS, the second symbol subset consisting of a fourth symbol quantity of the symbols of the symbol group, the fourth symbol quantity being bigger than the second symbol quantity, and the second symbol subset being less than fully staggered in the frequency domain.
Clause 46. The storage medium of clause 37, wherein the processor-readable instructions configured to cause the processor to select the symbol subset include processor-readable instructions configured to cause the processor to select the symbol subset based on a time between occasions of the OFDM PRS.
Clause 47. The storage medium of clause 37, wherein the processor-readable instructions configured to cause the processor to select the symbol subset include processor-readable instructions configured to cause the processor to select the symbol subset based on motion of the user equipment.
Clause 48. The storage medium of clause 37, wherein the processor-readable instructions configured to cause the processor to select the symbol subset include processor-readable instructions configured to cause the processor to select the symbol subset based on a bandwidth of the symbol subset.
Other Considerations
Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software and computers, functions described above can be implemented using software executed by a processor, hardware, firmware, hardwiring, or a combination of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.
As used herein, the singular forms “a,” “an,” and “the” include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “includes,” and/or “including,” as used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Also, as used herein, “or” as used in a list of items (possibly prefaced by “at least one” of or prefaced by “one or more of”) indicates a disjunctive list such that, for example, a list of “at least one of A, B, or C,” or a list of “one or more of A, B, or C” or a list of “A or B or C” means A, or B, or C, or AB (A and B), or AC (A and C), or BC (B and C), or ABC (i.e., A and B and C), or combinations with more than one feature (e.g., AA, AAB, ABBC, etc.). Thus, a recitation that an item, e.g., a processor, is configured to perform a function regarding at least one of A or B, or a recitation that an item is configured to perform a function A or a function B, means that the item may be configured to perform the function regarding A, or may be configured to perform the function regarding B, or may be configured to perform the function regarding A and B. For example, a phrase of “a processor configured to measure at least one of A or B” or “a processor configured to measure A or measure B” means that the processor may be configured to measure A (and may or may not be configured to measure B), or may be configured to measure B (and may or may not be configured to measure A), or may be configured to measure A and measure B (and may be configured to select which, or both, of A and B to measure). Similarly, a recitation of a means for measuring at least one of A or B includes means for measuring A (which may or may not be able to measure B), or means for measuring B (and may or may not be configured to measure A), or means for measuring A and B (which may be able to select which, or both, of A and B to measure). As another example, a recitation that an item, e.g., a processor, is configured to at least one of perform function X or perform function Y means that the item may be configured to perform the function X, or may be configured to perform the function Y, or may be configured to perform the function X and to perform the function Y. For example, a phrase of “a processor configured to at least one of measure X or measure Y” means that the processor may be configured to measure X (and may or may not be configured to measure Y), or may be configured to measure Y (and may or may not be configured to measure X), or may be configured to measure X and to measure Y (and may be configured to select which, or both, of X and Y to measure).
As used herein, unless otherwise stated, a statement that a function or operation is “based on” an item or condition means that the function or operation is based on the stated item or condition and may be based on one or more items and/or conditions in addition to the stated item or condition.
Substantial variations may be made in accordance with specific requirements. For example, customized hardware might also be used, and/or particular elements might be implemented in hardware, software (including portable software, such as applets, etc.) executed by a processor, or both. Further, connection to other computing devices such as network input/output devices may be employed. Components, functional or otherwise, shown in the figures and/or discussed herein as being connected or communicating with each other are communicatively coupled unless otherwise noted. That is, they may be directly or indirectly connected to enable communication between them.
The systems and devices discussed above are examples. Various configurations may omit, substitute, or add various procedures or components as appropriate. For instance, features described with respect to certain configurations may be combined in various other configurations. Different aspects and elements of the configurations may be combined in a similar manner. Also, technology evolves and, thus, many of the elements are examples and do not limit the scope of the disclosure or claims.
A wireless communication system is one in which communications are conveyed wirelessly, i.e., by electromagnetic and/or acoustic waves propagating through atmospheric space rather than through a wire or other physical connection. A wireless communication network may not have all communications transmitted wirelessly, but is configured to have at least some communications transmitted wirelessly. Further, the term “wireless communication device,” or similar term, does not require that the functionality of the device is exclusively, or evenly primarily, for communication, or that the device be a mobile device, but indicates that the device includes wireless communication capability (one-way or two-way), e.g., includes at least one radio (each radio being part of a transmitter, receiver, or transceiver) for wireless communication.
Specific details are given in the description to provide a thorough understanding of example configurations (including implementations). However, configurations may be practiced without these specific details. For example, well-known circuits, processes, algorithms, structures, and techniques have been shown without unnecessary detail in order to avoid obscuring the configurations. This description provides example configurations only, and does not limit the scope, applicability, or configurations of the claims. Rather, the preceding description of the configurations provides a description for implementing described techniques. Various changes may be made in the function and arrangement of elements.
The terms “processor-readable medium,” “machine-readable medium,” and “computer-readable medium,” as used herein, refer to any medium that participates in providing data that causes a machine to operate in a specific fashion. Using a computing platform, various processor-readable media might be involved in providing instructions/code to processor(s) for execution and/or might be used to store and/or carry such instructions/code (e.g., as signals). In many implementations, a processor-readable medium is a physical and/or tangible storage medium. Such a medium may take many forms, including but not limited to, non-volatile media and volatile media. Non-volatile media include, for example, optical and/or magnetic disks. Volatile media include, without limitation, dynamic memory.
Having described several example configurations, various modifications, alternative constructions, and equivalents may be used. For example, the above elements may be components of a larger system, wherein other rules may take precedence over or otherwise modify the application of the invention. Also, a number of operations may be undertaken before, during, or after the above elements are considered. Accordingly, the above description does not bound the scope of the claims.
A statement that a value exceeds (or is more than or above) a first threshold value is equivalent to a statement that the value meets or exceeds a second threshold value that is slightly greater than the first threshold value, e.g., the second threshold value being one value higher than the first threshold value in the resolution of a computing system. A statement that a value is less than (or is within or below) a first threshold value is equivalent to a statement that the value is less than or equal to a second threshold value that is slightly lower than the first threshold value, e.g., the second threshold value being one value lower than the first threshold value in the resolution of a computing system.
Claims
1. A user equipment comprising:
- a receiver configured to receive a wireless orthogonal frequency division multiplexed (OFDM) positioning reference signal (PRS);
- a memory; and
- a processor, communicatively coupled to the receiver and the memory, configured to: select a symbol subset of a symbol group of the OFDM PRS, the OFDM PRS comprising a slot of symbols comprising the symbol group, the symbol group consisting of a first symbol quantity of consecutive ones of the symbols, the symbol group being fully staggered in frequency domain, the symbol subset consisting of a second symbol quantity of the symbols of the symbol group, the second symbol quantity being smaller than the first symbol quantity, and the symbol subset being less than fully staggered in the frequency domain; and measure the symbol subset without measuring all of the symbols of the symbol group.
2. The user equipment of claim 1, wherein subcarriers of the symbol subset are uniformly spaced in the frequency domain.
3. The user equipment of claim 1, wherein the symbol subset comprises at least two consecutive symbols of the symbol group.
4. The user equipment of claim 1, wherein the processor is configured to select the symbol subset based on at least one of a desired processing reduction or a desired power consumption reduction.
5. The user equipment of claim 1, wherein the processor is configured to select the symbol subset based on a third symbol quantity of consecutive ones of the symbols that include all symbols of the symbol subset, the third symbol quantity being smaller than the first symbol quantity.
6. The user equipment of claim 1, wherein the slot is a second slot, the OFDM PRS comprises a first slot comprising the symbol group, and wherein the processor is configured to obtain a measurement of the symbol group of the first slot and to select the symbol subset based on a metric of the measurement.
7. The user equipment of claim 6, wherein the processor is configured to select the symbol subset based on the metric of the measurement meeting a corresponding threshold quality and the processor being able to decode a time of arrival of the OFDM PRS using less than all of a symbol of the OFDM PRS.
8. The user equipment of claim 1, wherein the processor is configured to select the symbol subset in response to an indication that the user equipment is nearing a source of the OFDM PRS.
9. The user equipment of claim 1, wherein the symbol subset is a first symbol subset, and wherein the processor is configured to select a second symbol subset of the symbol group in response to an indication that the user equipment is moving away from a source of the OFDM PRS, the second symbol subset consisting of a fourth symbol quantity of the symbols of the symbol group, the fourth symbol quantity being bigger than the second symbol quantity, and the second symbol subset being less than fully staggered in the frequency domain.
10. The user equipment of claim 1, wherein the processor is configured to select the symbol subset based on a time between occasions of the OFDM PRS.
11. The user equipment of claim 1, wherein the processor is configured to select the symbol subset based on motion of the user equipment.
12. The user equipment of claim 1, wherein the processor is configured to select the symbol subset based on a bandwidth of the symbol subset.
13. A method of measuring a wireless orthogonal frequency division multiplexed (OFDM) positioning reference signal (PRS) at a user equipment, the method comprising:
- selecting a symbol subset of a symbol group of the OFDM PRS, the OFDM PRS comprising a slot of symbols comprising the symbol group, the symbol group consisting of a first symbol quantity of consecutive ones of the symbols, the symbol group being fully staggered in frequency domain, the symbol subset consisting of a second symbol quantity of the symbols of the symbol group, the second symbol quantity being smaller than the first symbol quantity, and the symbol subset being less than fully staggered in the frequency domain; and
- measuring the symbol subset without measuring all of the symbols of the symbol group.
14. The method of claim 13, wherein subcarriers of the symbol subset are uniformly spaced in the frequency domain.
15. The method of claim 13, wherein the symbol subset comprises at least two consecutive symbols of the symbol group.
16. The method of claim 13, wherein the symbol subset is selected based on at least one of a desired processing reduction or a desired power consumption reduction.
17. The method of claim 13, wherein the symbol subset is selected based on a third symbol quantity of consecutive ones of the symbols that include all symbols of the symbol subset, the third symbol quantity being smaller than the first symbol quantity.
18. The method of claim 13, wherein the slot is a second slot, the OFDM PRS comprises a first slot comprising the symbol group, and the method further comprises obtaining a measurement of the symbol group of the first slot, wherein the symbol subset is selected based on a metric of the measurement.
19. The method of claim 18, further comprising decoding a time of arrival of the OFDM PRS at the user equipment, wherein the symbol subset is selected based on the metric of the measurement meeting a corresponding threshold quality and the time of arrival being able to be decoded by the user equipment using less than all of a symbol of the OFDM PRS.
20. The method of claim 13, wherein the symbol subset is selected in response to an indication that the user equipment is nearing a source of the OFDM PRS.
21. The method of claim 13, wherein the symbol subset is a first symbol subset, and wherein the method further comprises selecting a second symbol subset of the symbol group in response to an indication that the user equipment is moving away from a source of the OFDM PRS, the second symbol subset consisting of a fourth symbol quantity of the symbols of the symbol group, the fourth symbol quantity being bigger than the second symbol quantity, and the second symbol subset being less than fully staggered in the frequency domain.
22. The method of claim 13, wherein the symbol subset is selected based on a time between occasions of the OFDM PRS.
23. The method of claim 13, wherein the symbol subset is selected based on motion of the user equipment.
24. The method of claim 13, wherein the symbol subset is selected based on a bandwidth of the symbol subset.
25. A user equipment comprising:
- means for receiving a wireless orthogonal frequency division multiplexed (OFDM) positioning reference signal (PRS);
- means for selecting a symbol subset of a symbol group of the OFDM PRS, the OFDM PRS comprising a slot of symbols comprising the symbol group, the symbol group consisting of a first symbol quantity of consecutive ones of the symbols, the symbol group being fully staggered in frequency domain, the symbol subset consisting of a second symbol quantity of the symbols of the symbol group, the second symbol quantity being smaller than the first symbol quantity, and the symbol subset being less than fully staggered in the frequency domain; and
- means for measuring the symbol subset without measuring all of the symbols of the symbol group.
26. The user equipment of claim 25, wherein subcarriers of the symbol subset are uniformly spaced in the frequency domain.
27. The user equipment of claim 25, wherein the symbol subset comprises at least two consecutive symbols of the symbol group.
28. The user equipment of claim 25, wherein the means for selecting the symbol subset include means for selecting the symbol subset based on at least one of a desired processing reduction or a desired power consumption reduction.
29. The user equipment of claim 25, wherein the means for selecting the symbol subset include means for selecting the symbol subset based on a third symbol quantity of consecutive ones of the symbols that include all symbols of the symbol subset, the third symbol quantity being smaller than the first symbol quantity.
30. A non-transitory, processor-readable storage medium comprising processor-readable instructions configured to cause a processor of a user equipment, in order to measure a wireless orthogonal frequency division multiplexed (OFDM) positioning reference signal (PRS), to:
- select a symbol subset of a symbol group of the OFDM PRS, the OFDM PRS comprising a slot of symbols comprising the symbol group, the symbol group consisting of a first symbol quantity of consecutive ones of the symbols, the symbol group being fully staggered in frequency domain, the symbol subset consisting of a second symbol quantity of the symbols of the symbol group, the second symbol quantity being smaller than the first symbol quantity, and the symbol subset being less than fully staggered in the frequency domain; and
- measure the symbol subset without measuring all of the symbols of the symbol group.
Type: Application
Filed: Sep 7, 2021
Publication Date: Mar 10, 2022
Patent Grant number: 11950210
Inventors: Alexandros MANOLAKOS (Escondido, CA), Mukesh KUMAR (Hyderabad), Srinivas YERRAMALLI (San Diego, CA)
Application Number: 17/467,659
